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Phosphorylation of syntaxin‐3 at Thr 14 negatively regulates exocytosis in RBL‐2H3 mast cells
Author(s) -
Tadokoro Satoshi,
Shibata Tetsuhiro,
Inoh Yoshikazu,
Amano Toshiro,
Nakanishi Mamoru,
Hirashima Naohide,
UtsunomiyaTate Naoko
Publication year - 2016
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1002/cbin.10600
Subject(s) - syntaxin 3 , exocytosis , syntaxin , munc 18 , microbiology and biotechnology , phosphorylation , mast cell , stx1a , snare complex , chemistry , biology , biochemistry , synaptic vesicle , secretion , immunology , vesicle , membrane
Recent studies have revealed that soluble N‐ethylmaleimide‐sensitive factor attachment protein receptor (SNARE) proteins interact with each other, forming a SNARE complex that induces exocytosis in mast cells. Previously, we reported that syntaxin‐3, a SNARE protein, regulates mast cell exocytosis and is constantly phosphorylated. In this study, we tried to identify the amino acid residue that is phosphorylated in mast cells, and to elucidate the regulatory mechanism of exocytosis by phosphorylation in syntaxin‐3. We found that Thr 14 of syntaxin‐3 was a phosphorylation site in mast cells. In addition, the overexpression of a constitutively dephosphorylated syntaxin‐3 (T14A) mutant enhanced mast cell exocytosis. We also showed that the phosphomimetic mutation of syntaxin‐3 at Thr 14 (T14E) induced structural changes in syntaxin‐3, and this mutation inhibited binding of syntaxin‐3 to Munc18‐2. These results suggest that phosphorylated syntaxin‐3 at Thr 14 negatively regulates mast cell exocytosis by impairing the interaction between syntaxin‐3 and Munc18‐2.